Refrigerating machine



His Attorney.

L. W. ATCHISON REFRIGERATING MACHINE Filed July 1, 1941 Fig.

I /3 ai 34 3E 37 Leonard W. Atchison,

March 2, '1943.-

Patented Mar. 2, 1943 nEFRrGERA'rING Leonard W. Atchison, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application July 1, 1941, Serial No. 400,588

claims. (ci. sra- 116) i My invention relates to refrigerating machines,

and more particularly to such machines having i cooling units arranged to provide a plurality of zones operating at different temperatures.

Refrigerating machines, and particularly household refrigerators, are commonly provided with evaporators which are designed to provide adequate'surface to cool the air in the cabinet and also a low temperature zone in which water, desserts, and the like may be frozen. Some evaporators for this purpose have been designed with one evaporator arranged within the other. The freezing zone is defined and cooled`by the inner evaporator and a higher temperature cooll ing zone is refrigerated by the outer evaporator. AThis arrangement permits the inner evaporator to be operated at a,relatively low temperature and the outer evaporator at a relatively high temperature. If the inner evaporator is completely or substantially enclosed the air'in the food compartment will not circulate through the freezing zone where a substantial quantity of moisture would be removed from the air, thereby minimizing the Aaccumulation of frost on the walls of the inner evaporator and thereby increasing the time between defrosting periods. The rate of de-` hydration of food in the refrigerator cabinet may be minimized since the cabinet evaporator mayv be maintained at temperatures above freezing, in

which case no frost will accumulate on the warmer outer evaporator.

Accordingly, it is an' object of my invention to provide a Arefrigerating machine having anl improved cooling umt for establishing a plurality `of cooling zones in a refrigerator cabinet.

Another `object of my invention is to provide a. refrigerating machine including an evaporator Fig. l; and Fig. 3 illustrates a detail of a modification of the arrangement shown in Fig. 1. I have shown a refrigerator cabinet of the domestic type including a food storage compart-` ment IIl normally closed by a door (not shown) and a cooling unit II arranged within the compartment I0. A suitable refrigerant liquefying and circulating means is provided but inasmuch as the details thereof form no part of the present invention and conventional apparatus may be employed, it is believed unnecessary to illustrate the details thereof. It will be understood that a condensing unit will be provided for vcompressing gaseous refrigerant withdrawn from the cooling having a plurality of sections and an improved arrangement for maintaining each of said sections at a different temperature.

vFurther objects and advantages of my invention will-become apparent as the following description proceeds, and the features ofnovelty which characterize my invention will -be pointed out withparticularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention,

.reference may be had to the accompanying drawing in which Fig. 1 is a front elevation of the upper portion of a household refrigerator machine containing a cooling unit embodying the principles of my invention; Fig. 2 is a sectional view taken along the line 2-2 of Fig. 1 illustrating the arrangement of the cooling unit disclosed in unit or refrigerant evaporator II, cooling and liquefying the refrigerant and returning the liquid refrigerant tothe cooling unit through a receiver or oat valve chamber I2. When a'predetermined quantity of liquid refrigerant hascollected in the chamber I2, a float therein rises andthe liquid refrigerant flows through conduits I3 and I4 to the inner evaporator I5. The liquid refrigerant within vthe evaporator I5 is vaporized by the absorption of heat from the air within the freezing zone I6, defined by the inner evaporator I5, and from articles placed within the freezing zone, and the vaporized refrigerant is withdrawn through a suction line II and returned to the condensing unit. There is provided control mechanism including a thermostatic element I8 secured adjacent the outer portion of the evaporator i5, the motor 'within the condensing unit being started and stopped by the control mechanism in response 4to the temperature of the thermostatic element provide adequate surface for cooling the air adjacentthe surfaces thereof Land a plurality of surfaces for supportingfreezing trays and the like.

As best seen in Fig. 2, the evaporatorl5 is made of inner and outer sheet metal portions `2I and 22, respectively, the outer lportion 22 being corrugated to provide a plurality of depending 'refrigerant circulating passages or conduits 20, although both sheets 2| and 22 are provided with indentations to provide'a header I9. Portions of the refrigerant passages are arranged in the freezing tray supporting surfaces so as topro# vide for the absorption of heat from the freezing trays and-the like. The sheets are suitably joined together as by welding. for example, and then turning over the marginal edges of the inner relalower and upper surfaces for supporting freezing trays and the like. A -metal sheet 23 may be secured as by welding to the upper end of the side wall opposite the header and constitutes a side wall for an upper freezing chamber.

The evaporator I5 is designed to run at a relatively low temperature and provide within it a cold compartment or zone I6 for keeping frozen foods, freezing water, desserts, and the like. I have provided a shield 24 disposed between the evaporator I5v and that part of the food storage compartment III exterior to the evaporator I5. 'I'he shield preferably is arranged to provide a complete enclosure for the evaporator- I5. As best seen in Fig. 2, in the form of my invention illustratedand described herein, the shield 24 is open at the front and rear, but the cooling unit is so disposed that the rear wall 25 of the refrigerator cabinet abuts the rear edges of the shield 24 and thereby provides a rear wall therefor. The shield is provided with inwardly directed flanges 26. at the front end thereof thereby closing the space between the shield 24 and the evaporator I5. In order to close the front end of the evaporator I5 there is provided a sheet metal door 21 which may be hinged to the flange 26, as indicated by the numeral 28.

In the form ofmy invention illustrated in the drawing the shield 24 is provided with refrigerant passages. In other words, the shield takes the form of a second evaporator thereby providing a cooling unit having one evaporator arranged within a second evaporator. The shield or evaporator 24 may be formed in a manner similar to the` evaporator I5 in that a pair of sheet lmetal members 29 and 3U may be provided, the outer member 3,0 being provided with a series of horizontally disposed corrugations 40 connected together by vertical corrugations 4I to provide a series of refrigerant passages on each end of the ow controlling means in the form of a solenoid operated valve 31 in the liquid refrigerant supply line to the outer evaporator. In order to con- !trol the solenoid valve I have provided means responsive to or related to the compartment air temperature, as for example, a thermostatic de vice 38 connected in an electrical circuit including the coil 39 of the solenoid operated valve'I the thermostat 38, and a suitable source of power. In the form of my invention shown in the drawing the thermostatic device is suitably supported on a side wall of the food storage compartment I0, but it'will be understood that any suitable dis' position' of the temperature responsive device may be employed. For example, the temperature responsive device could take the form of a thernostatic bulb containing an expansible liquid and arranged in contact with the shield Qr evaporator 24. Furthermore, it is entirely possible to provide a mechanically operated valve in the place of the solenoid operated vvalve which will serve the functions heretofore described.

In normal operation of a refrigerator cabinet of the domestic type the food'storage compartment Will be adequately cooled by the inner eva/porator I5. However, in case a heavy load is imlposed on the main food compartment Ill so that A the temperature of thebox air tends to rise -unsheet. The sheets may be suitably joined together to provide duid-tight passages as by means of welding, brazing, or the like and then bent into a substantially U-shape. The outer evap orator may alsobe a piece of sheet metal with tubing soldered or brazed to it to provide a refrigerant conduit and the assembly then bent into a U-shape. Two sets of refrigerant passages are by means of a: T-connection 34. Means is provided for withdrawing gaseous refrigerant from the outer evaporator in the form of a conduit or tube 35 communicating between, the upper passage of the refrigerant conducting section remote from the liquid refrigerant supply conduit 33, and

the upper portion of the header I9. The outer evaporator 24 may be suitably supported from the top wall of the compartment I0 by means of sheet metal brackets 36 suitably secured, as by welding, to the upper edge of the evaporator and to the top wall of the compartment. If desired,` l the brackets 36 may be integral with one or the other of the sheets 29 or 30.

In order to control the supply of l1quid refrigl erant to the outer evaporator I have provided duly, the refrigerant capacity of the outer evaporator or shield will be made available through operation of the solenoid valve in response to action of the ther-mostatic device, allowing some of the liquid refrigerant from the float chamber I2 to ow through the conduit 32, valve 31 and con-7 duit 33 into the fluid or refrigerant conveying passages in the shield. Thus, when additional refrigeration is required the whole Aouter shield, or parts of it according to the disposition of the refrigerant passages, can be made to serve as an evaporator running at a somewhat higher temperature than the evaporator I5 to .compensate for the greater load and augment the cooling capacity of the refrigeration apparatus.

Modifications will occur to those skilled'in the art. For example, the evaporator I5 and the shield 24 may be Operated continually as evaporators, and the space between the evaporators Il and 24 may be filled with suitable heat insulating material, thereby minimizing the transfer of heat between the two evaporators. With such an a'rrangement the outer member 24 would serve as a shield for preventing the' box air from circulating across the walls of the evaporator I5 but the evaporator function of the shield member 24 must be relied upon entirely to provide cooling for the food storage compartment 1 0.

While I have described what I at .present consider. 'the preferred embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may b'e made without departing from my invention. For example, I may provide a restriction 42 in the conduit I4 as shown in Fig. 3, as a capillary tube', -for example, for preventing excessive fiow of liq- -uid refrigerant to the evaporator I5. Such a .restriction also insures a substantial flow -of liquid refrigerant to the outer evaporator or shield What I claim as new and desire to secure by.

LettersPatent of the United States is:

1. In a refrigeratng machine including a cabinet having a food 'storage compartment to be cooled and a refrigerant circulating system cornprising a cooling unit arranged within said food compartment and refrigerant flow-controlling means for controlling the iiow of liquid refrigerant to said unit, said cooling unit comprising two evaporators connected in parallel relationship in said system and arranged one within the other, means for supplying refrigerant to said inner one of said evaporators, said inner one of said evaporators being. of theilooded type and having a header and a plurality of depending refrigerant circulating conduits, means for supplying refrigerant to the outer one of said evaporators, said outer one of said evaporators being of the dry type, ofw controlling means arranged in said last mentioned supply means for controlling' the flow of refrigerant to said outer evaporator, temperature responsive means for controlling said flow controlling means, and means for withdrawing the gaseous refrigerant from said evaporators. l

2. In a refrigerating machine including a cabinet having a food storage compartment to be cooled and a refrigerant circulating system cornprising a cooling unit arranged within said food storage compartment and refrigerant flow-controlling means for controlling the ilow of liquid refrigerantto said unit, said cooling unit comprising two evaporators connected in parallel in said system and arranged one within the other, means for supplying refrigerant to the inner one of said evaporators, said inner one of said evaporators being of the flooded type, said supply` means also being arranged for supplying refrigerant to the outer one of said evaporators, said outer one of said evaporators. being of the dry type, means including a solenoid operated valve arranged in said last mentioned supply means for controlling the flow of refrigerant to said outerevaporator, means responsive to the compartment air temperature for controlling the operation of said valve, and means for withdrawing gaseous refrigerant from said evaporator,

3. In a refrigerating machine including a cabinet having a food storage compartment to be cooled and a refrigerant circulating system comprising a cooling unit `arranged within said food storage compartment, said cooling unit'having portions connected in parallel in said system and arranged one within the other in order to provide a freezing zone and a cooling zone, means for supplying refrigerant to the freezing portion of said cooling unit, said freezing portion being of the flooded type, means for supplying refrigerant to the cooling portion of said evaporator, said cooling portion of said evaporator being'of the drytype, flow controlling means arranged in i said last mentioned supply means for controlling the flow of refrigerant to said cooling portion, temperature responsive means for controlling said iiow controlling means, and means for withdrawing gaseous refrigerant from said portion.

4. In a refrigerating machine including a cabinet having a food storage compartment to be cooled and a refrigerant circulating system comprising a cooling unit arranged within said food storage compartment, means for supplying liquid refrigerant to said cooling unit, said cooling unit being of the flooded type, a shield member disposed about and spaced .from said cooling unit and substantially enclosing said cooling unit, said shield member being provided with auxiliary refrigerant circulating passages, means connecting said passages in parallel circuit relationship -with said cooling unit, flow controlling means arranged for controlling the ow of refrigerant to saidauxiliary passages, temperature responsive means for controlling said flow controlling means whereby said auxiliary passages augment the cools ing capacity of the cooling units, and means for withdrawing gaseous refrigerant from said cooling unit and said auxiliary passages.

5. In a refrigerating machine of the type comprising a cabinet provided with a food storage compartment to be cooled and a refrigerant cir- A culating system including a cooling unit inv said compartment and refrigerant flow-controlling means for controlling the flow of liquid refrigerant to said unit, said cooling unit comprising two evaporators connected in parallel in said system and arranged one within the other, the inner evaporator being of the flooded type and having a.l

ygaseous refrigerant from said evaporators.

LEONARD W. ATcmsvoN. 

